Ability of Lipid Hydroperoxides To Partition into Surfactant Micelles and Alter Lipid Oxidation Rates in Emulsions

Abstract

Lipid hydroperoxides are important factors in lipid oxidation due to their ability to decompose into free radicals. In oil-in-water emulsions, the physical location of lipid hydroperoxides could impact their ability to interact with prooxidants such as iron. Interfacial tension measurements show that linoleic acid, methyl linoleate, and trilinolein hydroperoxides are more surface-active than their non-peroxidized counterparts. In oil-in-water emulsion containing surfactant (Brij 76) micelles in the continuous phase, linoleic acid, methyl linoleate, and trilinolein hydroperoxides were solubilized out of the lipid droplets into the aqueous phase. Brij 76 solubilization of the different hydroperoxides was in the order of linoleic acid > trilinolein > or = methyl linoleate. Brij 76 micelles inhibited lipid oxidation of corn oil-in-water emulsions with greater inhibition of oxidation occurring in emulsions containing linoleic acid hydroperoxides. Surfactant solubilization of lipid hydroperoxides could be responsible for the ability of surfactant micelles to inhibit lipid oxidation in oil-in-water emulsions.

Mass Transport Phenomena in Lipid Oxidation and Antioxidation

“…As such, surface-active LOOHs could concentrate at the oil-water interfaces of bulk oils, oil-in-water emulsions, or membrane systems. Indeed, several authors have reported the presence of LOOH at the emulsion droplet surface (Dimakou et al 2007;Mancuso et al 2000;Mei et al 1998a,b;Nuchi et al 2002;Yoshida & Niki 1992). In membrane systems, LOOHs float on the LDL surface (Ingold et al 1993).…”

“…Twenty-eight formulations were associated with an estimated proportion of unadsorbed emulsifiers higher than 90%; 20 resulted in an unadsorbed proportion of 70-90%, and 13 in an unadsorbed proportion of 50-70%. There is abundant experimental evidence from studies using oil-in-water emulsions and microemulsions that unadsorbed surfactants present in the aqueous phase at concentrations higher than their critical micelle concentration (CMC) serve as vehicles for transferring antioxidants (Kiralan et al 2014;Laguerre et al 2009Laguerre et al , 2010Panya et al 2012;Richards et al 2002), hydroperoxides (Nuchi et al 2002), and iron (Cho et al 2002) from the oily phase to the aqueous one and/or the interface.…”

“…One of the major reaction products formed during the course of lipid oxidation are LOOHs, which, for some of them, are surface active (Nuchi et al 2002). As such, surface-active LOOHs could concentrate at the oil-water interfaces of bulk oils, oil-in-water emulsions, or membrane systems.…”

“…Using trilinolein, linoleic acid, and its methyl ester, Nuchi et al (2002) showed that all of the different peroxidized lipids were able to reduce interfacial tension between hexadecane and water more than their nonperoxidized parents. Among them, linoleic acid hydroperoxides are more surface active than methyl linoleate or trilinolein hydroperoxides.…”

Functionality of HDL: Antioxidation and Detoxifying Effects

“…Addition of a hydroperoxyl group to a phospholipid or cholesteryl ester molecule strongly increases hydrophilicity. As a result, LOOH molecules are more surface active than their non-peroxidised counterparts (Nuchi et al 2002). Their exposure to the aqueous phase at the HDL surface facilitates their removal from the lipoprotein.…”